The invention pertains to closed conduit systems utilized for the purpose of protecting an exterior water supply pipe for a heated dwelling from freezing.
In the most typical installation, the water service for mobile homes includes a vertical exterior service pipe rising from the ground adjacent the home, or from a pit disposed below or adjacent the home, which then travels horizontally to the location where the pipe enters the mobile home, usually through the floor. In northern climates, it is the common practice to insulate and heat the exterior water supply pipe of a mobile home water system to prevent freezing. Such protection consists of wrapping the exterior water pipe with an electrical heat tape of the resistance type and wrapping a thermal insulation, such as glass fibre, about the heat tape and pipe.
In such installations, the electric heat tape is energized during periods when freezing might occur, and it is the most common practice to leave the heat tape energized continually during cold weather. Such continuous use of electrical heat tapes of extended periods of time is relatively expensive, consumes substantial amounts of electrical energy, and most importantly, creates a safety hazard in that many mobile home fires are traced to faulty water pipe heat tapes. In particular, fires often occur at the location where the heat tape is disposed adjacent the mobile home floor or sub-floor where the exterior water pipe enters the home.
In U.S. Pat. No. 3,304,005 it is proposed to protect the exterior water pipe for mobile homes or trailers by encasing the pipes within a conduit system communicating with the forced hot air passage of the mobile home interior heating system. In the teaching of this patent a conduit system surrounds the exterior water pipe system and communicates with the home hot air passage to force hot air through the conduit system around the water pipe, and thereby prevent freezing. The hot air removed from the furnace passage is expelled into the atmosphere adjacent the water pipe region furtherest from the mobile home.
While the disclosure of U.S. Pat. No. 3,304,005 eliminates the necessity for heat tapes to prevent mobile home water systems from freezing it has the disadvantage of wasting heat energy since the heated air is expelled into the atmosphere, and is not recoverable. Further, as the hot air is expelled from the conduit system at the lowermost point of the system it is possible for dirt, leaves, and other foreign matter to accumulate about the conduit outlet ports, blocking such ports, and thereby preventing the necessary flow of heated air through the conduit system to avoid freezing.
In the practice of the present invention, deficiencies such as those mentioned above are overcome, and the advantages of the present invention are hereinafter described.